Melting point, melting temperature, fusion point (which is abbreviated to FP and often wrongly interpreted as flow point). The melting point is the temperature at which a solid passes from the solid into the liquid state. If the melting point is defined as the temperature at which the liquid and solid phases of a solid are in equilibrium (at a pressure of 760 torr), then the melting point is identical with the solidifying point or freezing point. Exact melting points can be determined in particular for pure solids with regular lattices and for many material blends of defined composition.

As a rule, amorphous materials and undefined material blends do not have a melting point but a melting range, i.e. they pass gradually from the solid into the liquid state over a certain temperature range. For materials with a large transition range, "substitute points" are determined instead of the melting point (e. g. the dropping point and the pour point). When sealing media with a working temperature close to its melting point, measures must be taken to ensure the medium in the stuffing box remains liquid in all operating states.